qt, refactor: Fix 'pixmap is deprecated' warnings

src/qt/bitcoingui.cpp

@@ -1305,7 +1305,7 @@ void BitcoinGUI::updateProxyIcon()
     bool proxy_enabled = clientModel->getProxyInfo(ip_port);
 
     if (proxy_enabled) {
-        if (labelProxyIcon->pixmap() == nullptr) {
+        if (!GUIUtil::HasPixmap(labelProxyIcon)) {
             QString ip_port_q = QString::fromStdString(ip_port);
             labelProxyIcon->setPixmap(platformStyle->SingleColorIcon(":/icons/proxy").pixmap(STATUSBAR_ICONSIZE, STATUSBAR_ICONSIZE));
             labelProxyIcon->setToolTip(tr("Proxy is <b>enabled</b>: %1").arg(ip_port_q));

src/qt/guiutil.cpp

@@ -929,4 +929,26 @@ QDateTime StartOfDay(const QDate& date)
 #endif
 }
 
+bool HasPixmap(const QLabel* label)
+{
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 15, 0))
+    return !label->pixmap(Qt::ReturnByValue).isNull();
+#else
+    return label->pixmap() != nullptr;
+#endif
+}
+
+QImage GetImage(const QLabel* label)
+{
+    if (!HasPixmap(label)) {
+        return QImage();
+    }
+
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 15, 0))
+    return label->pixmap(Qt::ReturnByValue).toImage();
+#else
+    return label->pixmap()->toImage();
+#endif
+}
+
 } // namespace GUIUtil

src/qt/guiutil.h

@@ -312,6 +312,14 @@ namespace GUIUtil
      */
     QDateTime StartOfDay(const QDate& date);
 
+    /**
+     * Returns true if pixmap has been set.
+     *
+     * QPixmap* QLabel::pixmap() is deprecated since Qt 5.15.
+     */
+    bool HasPixmap(const QLabel* label);
+    QImage GetImage(const QLabel* label);
+
 } // namespace GUIUtil
 
 #endif // BITCOIN_QT_GUIUTIL_H

src/qt/qrimagewidget.cpp

@@ -95,15 +95,12 @@ bool QRImageWidget::setQR(const QString& data, const QString& text)
 
 QImage QRImageWidget::exportImage()
 {
-    if(!pixmap())
+    return GUIUtil::GetImage(this);
-        return QImage();
-    return pixmap()->toImage();
 }
 
 void QRImageWidget::mousePressEvent(QMouseEvent *event)
 {
-    if(event->button() == Qt::LeftButton && pixmap())
+    if (event->button() == Qt::LeftButton && GUIUtil::HasPixmap(this)) {
-    {
         event->accept();
         QMimeData *mimeData = new QMimeData;
         mimeData->setImageData(exportImage());
@@ -118,7 +115,7 @@ void QRImageWidget::mousePressEvent(QMouseEvent *event)
 
 void QRImageWidget::saveImage()
 {
-    if(!pixmap())
+    if (!GUIUtil::HasPixmap(this))
         return;
     QString fn = GUIUtil::getSaveFileName(this, tr("Save QR Code"), QString(), tr("PNG Image (*.png)"), nullptr);
     if (!fn.isEmpty())
@@ -129,14 +126,14 @@ void QRImageWidget::saveImage()
 
 void QRImageWidget::copyImage()
 {
-    if(!pixmap())
+    if (!GUIUtil::HasPixmap(this))
         return;
     QApplication::clipboard()->setImage(exportImage());
 }
 
 void QRImageWidget::contextMenuEvent(QContextMenuEvent *event)
 {
-    if(!pixmap())
+    if (!GUIUtil::HasPixmap(this))
         return;
     contextMenu->exec(event->globalPos());
 }